Oil burner boiler



mmh 19, 1935. A, MACCHI wgmss OILl BURNER BOILER Original Filed June 16, 1933 Irwehto-r:

His Atbow'neg.

Patented Mar. 19, 1935 l UNITED STATES PATENToFFlcE .OIL BURNER BOILER,

Aldo Macchi, Schenectady, N. Y., assignor to General Electric Company, a corporation of New York v Application June 16, 1933, Serial No. 676,106

Renewed August 16, 1934 7 Claims. (CL 122-156) This application is a continuation in part of in burning oil so as to prevent the ame from my pending application, Serial No. 505,867, Oil contacting with water-backed surfaces .before and air arrangement for oil burner, led Decemthe combustion is completed. Furthermore, the ber 31, 1930. necessary surface area for effective absorption of The present invention relates to an improved the radiant heat from a low temperature llame 5 boiler construction particularly adaptedfor use of large volume is obtained. With oil burners in steam, hot water or vapor A Well extends downwardly from the top of the domestic heating service although not necessarily outer drum for receiving an oil burner atomizlimited thereto. ing nozzle or other fuel feeding mechanism and is l0 The principal object is to provide a boiler havjoined to the top of the combustion chamber 1o ing water-backed combustion chamber and secaround an axially alined opening provided therein ondary heat absorbing surfaces of proper arfor admitting the fuel downwardly into the rangement and proportion to obtain the maxichamber .along the axis thereof. At the bottom mum heat absorbing eiciency while at the same of the combustion chamber a combustion air intime permitting complete combustion of the fuel let opening opposing and axially alined with the 15 out of contact with the water-backed surfaces. fuel admitting opening is provided and connected Another object is to provide an improved boiler with an air conduit which extends exteriorly oi' that is specially adapted for eiectively'utilizing the outer drum. the heat developed by the method and means for In the space provided between the spaced apart producing combustion of my above identified Side walls of the combustion chamber shell and 20 pending application. the outer drum, tubular secondary heat absorb- A further object is to provide an improved ing means are nested alongside of the combusboiler of such construction that it is particularly tion chamber to form a water-backed exhaust adapted to have all the parts thereof welded into passage with an opening therefrom communicata single unit structure in which the parts are ing with the top of the combustion chamber 25 so correlated that they will automatically take adjacent the fuel admitting-opening and with a care of the forces produced by the pressures, exflue outlet conduit extending exterrly 0f the pansions or warpings that may occur during opouter boiler drum adjacent the bottom thereof. eration of the boiler without producing excessive This cOIIStIllCJOn 0f the tubular SeCODdary heat or dangerous strains in the boiler structure. absorbing means provides an effective heat trap 30 A further object is to provide an improved form whereby practically no heat is carried by conof boiler having a maximum size substantially vection currents from the interior of the boiler water-backed combustion chamber within a to the ue outlet when combustion is stopped. minimum size outer shell without unduly re- With the nozzle receiving well extending from the stricting the steam releasing area or the space top of the combustion chamber through the top 35 for the secondary heat absorbing surfaces of 0f the outer boiler drum of minimum cross secthe boiler. y tion practically no material restriction of the A still further object is to provide a. boiler con- Steam releasing area of the boiler is involvedA struction which serves automatically as a heat while at the same time fuel is readily admitted trap when the fuel burning mechanism is shut downwardly into the combustion chamber. A0 down. In the drawing illustrating the preferred em- Other objects will appear in the following debodiment of the Present invention, Fig. 1 is a scription. cross sectional view of the improved boiler show- Briefly, the improved boiler of the present ining the relatively large size combustion chamber vention consists, in the preferred form, of an and downwardly extending tubular secondary 45 outer metal shell or Water drum of a size which absorbing surfaces nested alongside thereof all can conveniently be handled and moved as a unit enclosed within the outer water drum to form a through doorways, passages, stairways and the unitary structure; FigJZ is a cross section of the like encountered in installing the boiler in domesboiler taken on line 2--2 showing the compactly tic service. Mounted inside of the outer shell adnested arrangement of the combustion chamber 50 jacent one side thereof is an inner metal shell and the secondary heat absorbing surfaces inside forming a combustion chamber of maximum size of the outer boiler water drum. vto provide the space required for eicient, noise- In Fig. 1 of the drawing the outer shell or waless and complete combustion of thefuel. This ter drum 10 of the boiler is of welded steel conlarge combustion space is particularly necessary struction and is shown covered with a heat insu- 65 lating jacket 1l which serves to prevent escape of the heat from the exterior of the boiler. A vertically extending cylindrical combustion cham- .ber 12 of maximum size is formed insde of the sure should ever develop within the combustion chamber.

The cylindrical inner shell 13 is provided with an axially alined opening 14 in the top thereof for admitting fuel downwardly into the combustion chamber 12. The collar 15 is welded between the top or crown sheet of the combustion chamber and the top of the outer water drum 10 to form a nozzle receiving wall 16. The oil burner atomizing nozzle mechanism 17 is shown located' in the well 16 as illustrated in the drawing although the well is adapted to receive other forms of fuel feeding mechanism.

At the bottom of the inner shell 13, the axially alined combustion air inlet opening 18 is formed oppositely and coaxially with the fuel admitting opening 14 and nozzle well 16. The combustion air conduit 19 is joined with the opening 18 and extends exteriorly of the outer water drum 10, joining with the main air supply conduit 20 which also supplies air through the conduits 21 around the nozzle mechanism 17. The butterfly valves 22 and 23 control the distribution of air from the main 20. The service door 10 being tightly closed at all times during normal operation, the combustion chamber 12 is thus sealed against the admission of air except for the opposing openings 14 and 18 which admit the combustible elements into the chamber.

The products of combustion are exhausted from the combustion chamber 12 through the exhaust conduit 25 which is joined tothe side wall of the inner shell 13 adjacent the top of the combustion chamber. Communicating with the exhaust conduit 25 is a tubular secondary heat absorbing means 26 extending downwardly in the space between the inner shell 13 and the outer water drum 10. In the preferred form of boiler illustrated this tubular secondary heat absorbing means 26 takes the form of a tubular casing 26 having a plurality of water coils 27 located interiorly thereof although it will be understood that other suitable forms of tubular secondary heat absorbing means may be employed, if desired.

The tubular casing 26 as shown in Fig. 2 is of kidney shape cross section so as to nest effectively into the curved space provided between the inner shell 13 and the outer drum 10 by locating the inner shell 13 and nozzle well off center adjacent the left-hand side"of the outer drum 10. This nested arrangement with eccentric location of the inner shell 13 permits a maximum size combustion chamber to be obtained while still providing ample space inside of the drum 10 for the, secondary heat absorbing surfaces as indicated in Fig. 2.

The flue outlet conduit 28 joins with the bottom of the secondary heat absorbing casing 26 and extends exteriorly of the water drum 10 so that it may be connected to a chimney when the boiler is installed for service. The outlet of the boiler for steam, hot water or vapor is indicated by the pipe 30 and the return by the pipe 31.

It will be observed that the lower portion of the combustion chamber 12 is shown provided with a refractory lining 32 and that an air box 33 with a baille 34 and a series of radially offset vanes 35 for imparting a whirling motion to the incoming combustion air all as set forth in my above identified application are provided in the bottom of the combustion chamber over the air inlet opening 18. On top of the air box 33 the refractory nozzle 33' is located. Also the bottom Wall of the combustion chamber is shown covered with a suitable layer of refractory material such as the refractory balls 36 indicated in the drawing.

In operation the water drum 10 of the improved boiler is filled with suicient water so that the normal level thereof is above the crown sheet of the combustion chamber as indicated in the drawing. When the means and method of combustion of vmy above identified application are employed fuel is admitted through the opening 14 and the nozzle well 15 downwardly into the top of the combustion chamber along the axis thereof and oppositely directed combustion air is admitted through the air opening 18 as indicated by the arrows in the drawing. The combustion of the fuel is completed in a low temperature flame within the space in the bottom of the boiler surrounded by the refractory walls. Practically all of the radiant heat of the low temperaure ame is absorbed by the large water-backed wall area of the combustion chamber without any appreciahle contact of the large volume of flame,

with these water-backed surfaces. Thus very eficient and complete combustion of the fuel can be obtained and at the same time the maximum amount of heat extracted directly therefrom in the combustion chamber.

The products of combustion rise adjacent the water-backed side walls and crown sheet of the combustion chamber and are conducted from the top of the combustion chamber through the water-backed exhaust conduit 25 into the tubular water-backed secondary heat absorbing means 26. The products of combustion then pass downwardly through the tubular secondary heat absorbing means 26, giving up heat to the secondary water-backed heat absorbing surfaces and finally passing out through the flue opening 28 adjacent the bottom of the water drum 10. Thisy long passage of the products of combustion adjacent water-backed surfaces serves to extract the major portion of any heat remaining therein.

When the combustion is stopped, the boiler serves effectively as a heat trap due to the fact that the tubular secondary heat absorbing casing 26 is directed downwardly and thus restricts the flow of any convection air currents from the interior of combustion chamber 12. The heat insulating jacket l1 effectively prevents escape of heat from the exterior of the boiler drum l0.

With the improved boiler construction of the present invention, the various metal parts of the boiler all may readily be joined together by electric or other forms of welding so asjto provide an efficient boiler unit of ample capacityand still be of a size and weight that may be conveniently handled and moved into a house for installation in domestic heating service. This avoids all the difculties and complications encountered in handling, assembling and installing a multiple part or sectional boiler such as ordinarily used in domestic heating service. Also the improved boiler construction insures water-backed heat absorbing surfaces around the sides of the combustion chamber and particularly over the crown sheet thereby limiting the temperature which the metal walls of the combustion chamber can attain when exposed to the temperature of combustion. This prevents excessive expansion and reduces warping and also prevents any serious deterioration of the metal of the combustion chamber walls due to high temperature. Furthermore, by forming the outer boiler casing in the form of a drum and the combustion chamber casing in the form of a cylinder, the side walls are capable of resisting any normal strains which may be imposed thereon with a minimum of stays. The collar 15 joining the top of the outer drum 10 and the top of the inner shell and forming the nozzle well serves mutually to stiifen and strengthen these parts against collapse due to pressures developed during operation of the boiler.

The relatively large size of the combustion chamber permits an abnormal percentage of the heat of combustion to be absorbed both by radiation from the low temperature ame of large volume and by contact with the heated products of combustion directly in the combustion chamber thereby reducing the amount of secondary heat absorbing surface required. At the same time the relatively large combustion chamber provides the necessary space required for noiseless, efficient and complete combustion of the fuel in accordance with the method and means of my pending application. The downwardly extending secondary heat absorbing surfaces are particularly effective in absorbing the heat remaining in the products of combustion before they are exhausted through the flue opening 28.

While the preferred form of the invention has been illustrated in connection with an oil burner, it will be understood that other fuels such as gas, coal or the like, may also be employed with advantages in the improved boiler construction. Likewise while the invention has been described in connection with a steam boiler, it will be understood that the same boiler may be used for hot wateror other service and that some modifications may be made in the detailed parts and arrangement of the improved boiler structure without departing from the scope and spirit of the invention set forth in the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States, iszl. A boiler furnace comprising an upright water drum, an inner shell mounted inside the Water drum adjacent one side thereof to form a combustion chamber having an air supply opening in the middle of the bottom thereof and having water-backed heat absorbing side walls and a water-backed heat absorbing crown sheet, a conduit forming a restricted passage extending from the combustion chamber upwardly through the middle of the water-backed crown sheet thereof and through the top of the water drum for admitting fuel downwardly into the combustion chamber, and tubular means forming a downwardly directed secondary water-backed heat absorbing passage nested in the space provided between said inner shell and the opposite side of said Water drum and having an inlet communicating with the top of the combustion chamber and an outlet extending exteriorly of said water drum. adjacent the bottom thereof.

2. A domestic boiler furnace of one piece welded construction comprising an upright water drum having a flue opening adjacent the bottom thereof and a fuel admitting well extending through the top thereof below the normal level of the water in the drum, an inner shell joined with said well to fo-rm an enlarged combustion chamber having water-backed side walls and crown sheet and provided with a combustion air inlet opening in the bottom thereof opposite said fuel admitting well, and a secondary heat absorbing conduit for exhausting the products of combustion laterally from the side of said inner shell adjacent the top thereof and extending `downwardly in the space between the inner shell and the water drum to connect with said flue opening.

3. A domestic oil burner boiler comprising an upright water drum having a flue opening formed therein adjacent the bottom thereof and an eccentric nozzle well extending through the top thereof below the normal level of the water in the drum, an inner cylindrical shell joined co-l axially with said Well to form an enlarged symmetrical `combustion chamber having an axial nozzle opening in the top thereof with waterbacked side walls and crown sheet and provided with a combustion air inlet opening in the bottom thereof coaxial with said nozzle opening, and an exhaust outlet conduit joined to the side of said inner shell adjacent the top thereof and extending downwardly in the space provided between the inner shell and the water drum to connect `with said flue opening.

4. A boiler furnace comprising a metal casing forming an airtight combustion chamber and having axially alined openings in the top and bottom thereof, conduits joined to said openings for admitting combustible elements into the chamber, an exhaust conduit extending from the side of said casing adjacent the top thereof, tubular means providing secondary heat absorbing surfaces joined with said exhaust conduit and extending downwardly adjacent said combustion chamber casing and provided with a ue outlet at the bottom thereof, and an outer drum forming a water-tight closure around said inner shell and tubular means.

5. A domestic oil burner boiler comprising a metal cylindrical casing forming a combustion chamber with a pair of axially alined openings in the ends thereof, conduits joined to said openings for admitting combustible elements into the chamber, an exhaust conduit joined to the side of said cylindrical casing to communicate with the combustion vchamber adjacent one end thereof, tubular means joined to said exhaust conduit to provide secondary heatabsorbing surfaces extending in spaced apart relation with said cylindrical casing and having a ue outlet adjacent the other end thereof, and an outer shell forming a water-tight container around said combustion chamber casing and secondary heat absorbing tubular means.

6. A heating furnace comprising an outer metal shell for containing a heating medium, an inner metal shell mounted inside the outer shell adjacent one side thereof to formv a sealed combustion chamber having heat absorbing walls in contact with the heating medium, a metal conduit joined between the outer shell and the inner shell for admitting fuel into the combustion chamber, a combustion air conduit joined to the combustion chamber opposite said fuel admitting conduit and extending exteriorly of the outer shell, and tubular metal conduit means joined to the combustion chamber adjacent said fuel admitting conduit and extending exteriorly of the outer shell for exhausting the products of combustion and providing secondary heat absorbing surfaces extending through the heat- 5 ing medium in spaced relation between the other side of said outer shell and said inner shell.

7. A boiler furnace comprising a metal drum forming a combustion chamber and having a conduit joined to each ed thereof for admit-r ting combustible elements into the chamber, and a metal exhaust conduit joined to the casing adjacent one end thereof and providing secondary hat absorbing surfaces and an outer metal drum forming a water-tight closure around said inner shell and said exhaust conduit.

ALDO MACCHI. 

